Electromagnetic linear actuator with movable plates and valve fluid regulator controlled by the actuator

ABSTRACT

An electromagnetic linear actuator having a stationary annular assembly with a magnetic outer shell and a magnetic inner core. Monostable or bistable control components may be mounted interchangeably between the outer shell and inner core. An assembly which is moveable in the axis of the annular assembly includes two magnetic plates which face the extremities of the annular assembly and a rod which is mounted so that it can slide inside the core. The first core is made of a material chosen for its frictional characteristics. The actuator may be used to control the valve of a regulator in the fuel supply circuit of a satellite engine.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates principally to an electromagnetic linear actuatordesigned to control a low-amplitude displacement.

This type of actuator may be used in numerous fields wherever there is aneed to control a low-amplitude linear displacement. It is of particularinterest in fields such as aeronautics and aerospace where reducing theweight and dimensions of actuators is crucial.

The invention also relates to a fluid regulator in which at least onevalve is controlled by an actuator according to the invention anddesigned particularly for use in ensuring the ergol supply of satelliteengines.

2. Discussion of the Background

Existing electromagnetic actuators comprise a ring-shaped stationaryassembly mainly constituted of means of electromagnetic control.Activating these electromagnetic control means creates a magnetic fluxthat controls the linear displacement of a magnetic core composed of acylindrical rod housed in such a way as it can slide inside thestationary assembly.

Such existing linear actuators can be divided into twostructurally-different groups depending on whether they are of themonostable or bistable type.

In monostable linear actuators the means of electromagnetic controlconsist solely of a trip coil. The power supply of this coil controlsthe displacement of the movable coil in a direction determined by thedirection of the current passing through the coil. Displacement of thecore in the opposite direction, determining the rest state of theactuator, may be effected by gravity, by a spring built into theactuator or by return means built into the apparatus controlled by theactuator.

In bistable linear actuators the means of electromagnetic controlcomprise at least one trip coil and at least one permanent magnet. Thepower supply of the coil or coils determines whether the movable core isdisplaced in one or the other direction depending on the direction ofthe current without the need for means of returning the core.

Both monostable and bistable movable core electromagnetic linearactuators are relatively large in size and are consequently relativelyheavy when a high magnetic flux is required.

In addition, using a movable core requires the creation of parts whosesurfaces in friction contact with one another are permeable to themagnetic flux. The choice of materials available is consequently verylimited and generally ill-suited to this type of friction contact.

Furthermore, movable core linear activators are usually manufacturedcompletely separately using different parts for monostable and bistabletype systems, which tends to increase production costs.

SUMMARY OF THE INVENTION

The aim of the present invention is to produce an electromagnetic linearactuator whose original design reduces size and weight for a given forcecompared with movable core actuators using the known art.

The invention also relates to an electromagnetic linear actuator whoseoriginal design gives prolonged service life and reduces heatingcompared with movable core linear actuators by enabling the movablecylindrical rod to be made of any friction-resistant material.

A further aim of the invention is to produce an electromagnetic linearactuator that can be made monostable or bistable by simply replacing theelectromagnetic control means, thereby significantly reducingmanufacturing costs when compared with existing actuators.

These three objectives are achieved by the invention using anelectromagnetic linear actuator comprising:

a stationary assembly in the form of a ring around an axis including,working from the outside inwards, a magnetic outer shell,electromagnetic control means and a magnetic inner core, two spacersbeing placed between the outer magnetic shell and the magnetic innercore on either side of the electromagnetic control means, and removablefastening means mechanically linking the magnetic inner core and theouter magnetic shell via the spacers, and

a movable assembly capable of moving in the said axis when theelectromagnetic control means are activated, said movable assemblyincluding at least one first magnetic plate positioned facing a firstextremity of the stationary assembly,

the actuator being constructed of standard mechanical parts suitable forbeing used with different types of electromagnetic control means.

In a preferred embodiment of the invention the actuator includes asecond magnetic plate positioned facing a second extremity of thestationary assembly and connected to the first magnetic plate by a rodthat masses through the stationary assembly in such way as to enable itto slide in the said axis a distance determined by the bearing of theplates on the corresponding extremities of the stationary assembly.

The various electromagnetic control means include monostable andbistable control means.

The monostable control means comprise a trip coil and the two spacersincluding a magnetic spacer and a non-magnetic spacer positioned oneither side of the trip coil.

Similarly, the bistable control means comprise a permanent magnetpositioned between two coils, the two spacers being non-magnetic andpositioned on either side of the coils.

In the preferred embodiment of the invention the outer magnetic shelland the magnetic inner core are linked by fasteners that simultaneouslypass through the outer magnetic shell, the spacers and the magneticinner core.

The invention also relates to a preferred application of said actuatorto controlling at least one valve in a fluid regulator of the type usedto ensure the ergol supply of satellite engines.

This application proposes a fluid regulator comprising at least onevalve controlled by an actuator according to the invention characterizedby the fact that the valve comprises:

a valve-seat formed in a passage through a stationary body, said seatbeing centered on a second axis parallel to the axis of the stationaryassembly of the actuator,

an actuating lever mounted so as to pivot in the stationary body arounda third axis at right angles to said second axis, said lever beingoriented more or less at right angles to the axis of the stationaryassembly of the actuator and the second and third axes,

a flap-type check valve fastened to a first extremity of the actuatinglever so as to constitute a leaktight seal when it presses on valve-seatin one position of the actuator,

a leaktight bellows disposed around the actuating lever, connected tosaid lever by a first extremity and connected to the stationary body bythe other extremity.

In a first embodiment the valve seat is plane and the flap is fastenedto the first extremity of the actuating lever by means for adjusting theorientation of the flap.

In a second embodiment the valve-seat is conical and the check-valve isspherical.

The above fluid regulator advantageously comprises at least a firstvalve controlled by a first actuator that includes bistableelectromagnetic control means and at least a second valve controlled bya second actuator that includes monostable electromagnetic controlmeans, the first and second valves being designed to be placed in thegiven order in a fluid supply circuit.

Where two fluids are to be regulated simultaneously, for example tosupply a satellite engine with two different ergols, the regulatorcomprises two first valves controlled simultaneously by the firstactuator and two second valves controlled simultaneously by the secondactuator, the first and second valves being designed to be placed in thegiven order in two parallel fluid supply circuits.

BRIEF DESCRIPTION OF THE DRAWINGS

Two preferred embodiments of the invention, given as non-restrictiveexamples, will now be described with reference to the attached drawingswhere:

FIG. 1 is a partial longitudinal cross-section that shows a monostableelectromagnetic linear actuator according to the invention; the upperhalf of the drawing shows the actuator in the rest state while the lowerhalf shows it in its activated state,

FIG. 2 is a similar view to that of FIG. 1 and shows a bistableelectromagnetic linear actuator according to the invention in the firstof its two stable states,

FIG. 3 shows the actuator of FIG. 2 when a change of state is commanded,

FIG. 4 shows the actuator of FIG. 2 in its second stable state, and

FIG. 5 is a partial cross section showing one application of actuatorsof FIGS. 1 through 4 to controlling the valves of a fluid regulator.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a monostable electromagnetic linear actuator according tothe invention. This actuator comprises a stationary assembly identifiedby the overall reference 10, together with a movable assembly identifiedby the overall reference 12.

Stationary assembly 10 is in the form of a ring around an axis 14.Working from the outside inwards, the assembly consists of a magneticouter shell 16, electromagnetic control means 18 and a magnetic innercore 20.

In the embodiment shown in FIG. 1, which concerns a monostable actuator,electromagnetic control means 18 consist essentially of a trip coil 22.On either side of this trip coil 22 spacers 24 and 26 are insertedbetween the outer magnetic shell 16 and the magnetic inner core 20.

One of the spacers 24 is preferably made of a non-magnetic materialwhile the other spacer 26 is made of a magnetic material. In a variantof the embodiment, spacers 24 and 26 may both be made of a non-magneticmaterial.

Spacers 24 and 26 provide a mechanical link between magnetic inner core20 and magnetic outer shell 16. More precisely, core 20 and shell 16 areassembled by means of spacers 24 and 26 and fastening means thatconsist, in the embodiment shown, of fastening stud pins 28 that aredriven through holes bored through core 20, spacers 24 and 26 and outermagnetic shell 16. In a variant of the embodiment, fastening stud pins28 may be replaced by any other easily-dismantled fastening devices suchas screws.

Movable assembly 12 of the monostable electromagnetic linear actuatorshown in FIG. 1 comprises a cylindrical rod 30 capable of sliding inaxis 14 inside a bore 32 cut through magnetic inner core 20 of thestationary assembly 10.

Movable assembly 12 also includes two magnetic plates 34 and 36 fastenedto cylindrical rod 30 on either side of stationary assembly 10 so thatthey are facing each extremity of this assembly. More precisely, thediameter of magnetic plates 34 and 36 is more or less the same as theexternal diameter of the ends of shell 16.

Magnetic plates 34 and 36 may be mounted on cylindrical rod 30 by anyconvenient means. For example, in the embodiment shown in FIG. 1,magnetic plate 34 is mounted on a threaded end-piece of rod 30 between anut 38 screwed onto said threaded end-piece and a shoulder formed on therod. Magnetic plate 36 is locked against the opposite end of cylindricalrod 30 by a fastening component (not shown) such as a screw axiallyinserted into rod 30.

In a variant of this embodiment, magnetic plate 36 may be made all inone piece with cylindrical rod 30. Since, however, it is possible forcylindrical rod 30 also to be made of a magnetic material, magneticplates 34 and 36 are preferably mounted on rod 30 which isadvantageously made of a different, non-magnetic material selected forits good friction characteristics.

When the monostable electromagnetic linear actuator shown in FIG. 1 isin the rest state, i.e. when trip coil 22 is not energized, movableassembly 12 is in the position shown in the upper half of the Figure.The actuator is maintained in this position by outside means (not shown)that may be gravity if axis 14 is disposed more or less vertically, orby external return means that are part of the apparatus (not shown)controlled by the actuator. In this rest state, magnetic plate 36presses against the corresponding extremity of stationary assembly 10while magnetic plate 34 is distanced from the other end of stationaryassembly 10 by a distance d that is the travel of the actuator.

When trip coil 22 is energized, the actuator moves into the activeposition shown in the lower half of FIG. 1. Energizing trip coil 22creates a magnetic flux whose force field passes successively throughmagnetic outer shell 16, magnetic spacer 26, magnetic inner core 20 andmagnetic plate 34 as indicated by letter L in the lower half of FIG. 1.Movable assembly 12 is therefore subjected to a force oriented alongaxis 14 which tends to displace the assembly towards the right ofFIG. 1. Magnetic plate 34 therefore presses against the correspondingend of stationary assembly 10 while magnetic plate 36 moves away fromthe other end of assembly 10 by distance d.

Displacement of movable assembly 12, i.e. movement of the actuator fromits rest to its active state, normally results in action on one or moreof the devices (not shown) it controls via at least one stud 40 fastenedto the surface of magnetic plate 36 facing outwards from the actuator.The length of stud 40 is preferably adjustable. For example, where thedevice controlled by the actuator is a valve, stud 40 acts, directly orindirectly, on the flap of the valve.

The stationary nature of magnetic inner core 20 combined with the use ofa movable assembly 12 comprising a magnetic plate 34, initiallydistanced from stationary assembly 10, means that rod 30 in frictioncontact with core 20 can be made of any suitable material. This materialcan therefore be selected for its friction characteristics, therebyincreasing the service life of the actuator and reducing heating.

The looping of force field L around magnetic plate 34 also generatesgreater force for a given size of actuator than is generated inconventional movable-core actuators. These improved performancecharacteristics enable the size and weight of actuators to be reduced,which is particularly important in the aeronautics and aerospaceindustries.

As shown by FIGS. 2 through 4, the monostable electromagnetic linearactuator of FIG. 1 can easily be converted into a bistableelectromagnetic linear actuator while retaining most of the mechanicalcomponents used to construct it.

For example, the only difference between stationary assembly 10' of thebistable actuator shown in FIGS. 2 through 4 and stationary assembly 10of the monostable actuator in FIG. 1 is the electromagnetic controlmeans 18' introduced between the magnetic outer shell 16 and magneticinner core 20. The movable assembly 12 also remains unchanged, i.e. itprincipally comprises a cylindrical rod 30 bearing magnetic plates 34and 36 facing each extremity of stationary assembly 10'.

In the embodiment shown in FIGS. 2 through 4 the electromagnetic controlmeans 18' comprise two trip coils 22a and 22b housed between shell 16and core 20 and offset from one another in axis 14. The electricitysupplies running through trip coils 22a and 22b flow in oppositedirections. Control means 18' also comprise a radially magnetizedpermanent magnet 42 positioned between coils 22a and 22b. Moreover,spacers 24 and 26' positioned between shell 16 and core 20 on eitherside of coils 22a and 22b are both non-magnetic.

Similarly to the monostable actuator shown in FIG. 1, the magnetic outershell 16 and the magnetic inner core 20 are assembled using stud pins 28that pass through holes bored in shell 16, spacers 24, 26' and core 20.

In FIG. 2 the bistable electromagnetic linear actuator is shown in afirst stable state similar to the rest state of the monostable actuatordescribed previously with reference to FIG. 1. However, instead of beingobtained due to external forces, this stable state is obtained naturallyby the flux created by magnet 42.

As shown at L1 in the upper half of FIG. 2, the magnet thereforegenerates a magnetic flux that flows successively through the magneticouter shell 16, magnetic plate 36 and magnetic inner core 20. Plate 36is thus pressed against one extremity of stationary assembly 10' suchthat the other plate 34 is moved away from the other end of stationaryassembly 10' by distance d.

The actuator goes into its second stable state, shown in FIG. 4, whentrip coils 22a and 22b are energized such that the magnetic flux isorientated in the opposite direction to that created by permanent magnet42. The flux thereby generated flows successively through shell 16,magnetic plate 34, core 20 and magnetic plate 36, as shown by L2 in FIG.3. The resulting flux present in the airgap between stationary assembly10' and magnetic plate 36 is canceled and the flux present in the airgapbetween stationary assembly 10' and magnetic plate 34" generates a forceof attraction along axis 14. Plate 34 is therefore pressed against oneextremity of stationary assembly 10' such that the other plate 36 ismoved away from the other end of the stationary assembly by distance d.

The position thereby obtained is preserved when the power supply to thecoil is cut since the flux of magnet 42 passes through magnetic plate 34as shown by L3 in the upper half of FIG. 4. The second stable positionis therefore achieved.

The actuator is returned to the first state illustrated by FIG. 2 byenergizing second coil 22a or 22b so that the magnetic flux is orientedin the opposite direction to that created by permanent magnet 42.

Whether monostable or bistable, the electromagnetic linear actuatoraccording to the invention acts on the device or devices (not shown) itcontrols via the stud or studs 40 shown on the right of FIGS. 1 to 4.

The embodiments of the electromagnetic linear actuator according to theinvention may be modified in various ways while remaining within theterms of the invention.

For example, in the monostable actuator described with reference to FIG.1, magnetic plate 36 may be eliminated and replaced with any type ofstop to limit the distance between magnetic plate 34 and the extremityof stationary assembly 10 to a predetermined distance d. In this variantit will be seen that the special structure of the actuator limits thisdistance d to a relatively small value.

In the bistable actuator described with reference to FIGS. 2 through 4,one of the two trip coils may be eliminated. The change from one stablestate to the other is then achieved using a single coil that isenergized with different polarities depending on the stable staterequired.

FIG. 5 shows an application of the monostable and bistable actuatorsthat have been described with reference to FIGS. 1 through 4 to thecontrol of fluid regulator valves. This application has beenparticularly designed for inclusion in two parallel circuits ensuringthe ergol supply of satellite engines (not shown) from two tanks (notshown) containing ergols under pressure.

The regulator, generally designated 44, comprises two identical valveassemblies disposed in parallel inside a single body 46, only one ofwhich is visible in FIG. 5. Each of these valve assemblies is designedto be mounted in one of the previously-mentioned parallel ergol supplycircuits.

Each of these valve assemblies comprises a first valve 50 and a secondvalve 48, mounted in series in this order inside passage 52 that passesthrough body 46. The two extremities of each passage 52 are fitted withconnectors (not shown) used to mount the regulator in the two fluidcircuits mentioned above.

Since valves 48 and 50 are identical, only one secondary valve 48 willbe described with reference to the numbers followed by the letter a. Thedescription applies equally to primary valves 50 where letter a shouldbe replaced by b.

Each secondary valve 48 comprises a valve-seat 54a formed in passage 52,from the center of which opens a section upstream of said passage.Beyond the valve-seat 54a, passage 52 widens out to form a chamber 56ahousing the flap 58a of valve 48.

Flap 58a of each valve 48 is fasted to a shaft at the end of anactuating lever 62a that pivots in body 46 of the regulator on axle 64a.More precisely, if the axle of valve-seat 54a is referred to as 66a,axles 64a and 66a are mutually perpendicular and both approximatelyperpendicular to longitudinal axis 68a of lever 62a.

In the configuration shown in FIG. 5, where axes 66a and 66b ofvalve-seats 48 and 50 are parallel to one another, as are axes 64a and64b of levers 62a and 62b, longitudinal axes 68a and 68b of levers 62aand 62b of the same valve assembly of the regulator are identical whenthe two valves are closed.

Shaft 60a bearing flap 58a is a disk-shaped protrusion of actuatinglever 62a and is parallel to longitudinal axis 66a of said lever. Saidshaft passes through the walls of chamber 56a; there is a certain degreeof play between the shaft and the walls. A first extremity of a metalsealing bellows 70a hermetically fastened to said disk-shaped section oflever 62a and surrounds an adjacent section of said lever. The other endof bellows 70a is fastened to a removable section of body 46 bearingaxle 64a.

The configuration described above ensures that chamber 56a is leaktightin relation to the exterior of regulator 44 without the force requiredto ensure the leaktightness of valve 48 being disrupted by the pressureof the force exerted by bellows 70a. Response time is therefore improvedand electrical consumption and weight are both reduced.

The use of flap 58a fastened to the end of lever 62a that actuates itincreases service life by avoiding any friction wear at this site.Leaktightness is also increased since no particles created by frictioncan come between flap 58a and seat 54a.

The stiffness of the connection between flap 58a and actuating lever 62amight prevent leaktight sealing of valve 48 if strict positioningtolerances are not complied with.

In order to overcome this drawback, flap 58a is fastened to shaft 60a bymeans of adjusting its orientation 72a when the plane surface of flap58a and seat 54a press against one another as shown in FIG. 5. Saidorientation adjustment means 72a comprise, for example, a sphericalsurface formed on shaft 60a trapped between two conical surfacesconnected to the flap together with a locking screw or nut.

In a variant of this embodiment such orientation adjustment means may beeliminated, flap 58a replaced by a ball and valve-seat 54a madefrustoconical in shape.

Actuating levers 62a and 62b extend beyond their axles 64a and 64b toprotrude from body 46 of regulator 44 where they can be actuated byactuators 74 and 76 respectively.

More precisely, a single actuator 76 acts on the two levers 62b tocontrol the two primary valves 50 simultaneously and a single actuator74 acts on the two levers 62a to control the two secondary valves 48simultaneously.

Actuator 76 is a bistable actuator of the type described above withreference to FIGS. 2 through 4. It controls the opening of primaryvalves 50 during the entire time an engine receives a fuel supply. Italso constitutes a safety device that closes the fuel supply circuits inthe event of secondary valves 48 getting stuck in the open position.

Actuator 74 is a monostable actuator identical to that described abovewith reference to FIG. 1. It can be used to control the precise movementof secondary valves 48 when the engine requires a supply of ergols.

The magnetic outer shells of actuators 74 and 76 are fastened by screws78 to a bracket of body 46 of regulator 44. The actuators are fastenedso that the respective axes 80 and 82 of stationary assemblies ofactuators 74 and 76 are parallel to one another and to axes 66a and 66bof valve-seats 48 and 50 and oriented at right angles to longitudinalaxes 68a and 68b of actuating levers 62a and 62b.

More precisely, actuator 74 acts simultaneously on the ends of the twolevers 62a via two studs 84 whose length is preferably adjustable. Alow-rating helical compression spring 86 is mounted on each stud 84 tomaintain the normal slight play between studs 84 and levers 62a in orderto prevent any transmission of vibrations.

Consequently the valves 48 are retained in the closed position both byreturn springs 88 disposed between the ends of levers 62a and a unit 90connected to the magnetic outer shell of actuator 74. Return springs 88are disposed along the axes of studs 84 on the other side of the levers62a from the studs. Springs 88 have a higher rating than springs 86.

Similarly, actuator 76 acts simultaneously on the ends of the two levers62b via two studs 92, preferably of adjustable length, that aremaintained very slightly distanced from the levers by helicalcompression springs 94. Return springs 96 bearing on unit 98 connectedto the magnetic outer shell of actuator 76 maintain valves 50 in theclosed position.

FIG. 5 shows the apparatus in the rest state. Valves 48 and 50 aremaintained closed by springs 88 and 96 alone.

When a satellite engine is to be supplied with ergols via the apparatusin FIG. 5, bistable actuator 76 is brought into its second stable state,resulting in displacement of studs 92 to the right of FIG. 5. Levers 62bthus control the simultaneous opening of the two primary valves 50.Valves 50 remain in this state until the supply of ergols isinterrupted.

As soon as opening of primary valves 50 is commanded, secondary valves48 are actuated so that they move in a controlled manner to supply theengine with the required quantities of ergols. This is effected bycontrolling monostable actuator 74 using electrical pulses whoseduration and spacing are controlled.

The application that has been described with reference to FIG. 5 is onlygiven as an example and should not be considered restrictive.

We claim:
 1. Electromagnetic linear actuator comprising:a stationaryassembly in the shape of a ring around an axis, including, working fromthe outside inwards, a magnetic outer shell, electromagnetic controlmeans and a magnetic inner core, two spacers being placed between theouter magnetic shell and the magnetic inner core on either side of theelectromagnetic control means, and removable fastening meansmechanically linking the magnetic inner core and the outer magneticshell passing through the spacers, and a movable assembly capable ofmoving in the said axis when the electromagnetic control means areactivated, said movable assembly including at least one first magneticplate positioned facing a first extremity of the stationary assembly,the actuator being constructed of standard mechanical parts suitable forbeing used with different types of electromagnetic control means. 2.Actuator of claim 1 in which movable assembly comprises a secondmagnetic plate positioned facing a second extremity of the stationaryassembly and connected to the first magnetic plate by a rod that passesthrough the stationary assembly in such way as to enable it to slide inthe said axis a distance determined by the bearing of the plates on thecorresponding extremity of the stationary assembly.
 3. Actuator asclaimed in claim 1 in which the various types of electromagnetic controlmeans comprises monostable control and bistable control means. 4.Actuator of claim 3 in which the monostable control means comprise atrip coil, the two spacers including a magnetic spacer and a nonmagneticspacer disposed on either side of the trip coil.
 5. Actuator of claim 3in which the bistable control means comprise a permanent magnet placedbetween two trip coils, the two spacers being non-magnetic andpositioned on either side of the trip coils.
 6. Fluid regulatorcomprising at least one valve controlled by an actuator according toclaim 1 in which the valve comprises:a valve-seat formed in a passagethrough a stationary body, said seat being centered on a second axisparallel to the axis of the stationary assembly of the actuator, anactuating lever mounted so as to pivot in the stationary body around athird axis at right angles to said second axis, said lever beingoriented more or less at right angles to the axis of the stationaryassembly of the actuator and the second and third axes, a flap fastenedto a first extremity of the actuating lever so as to constitute aleaktight seal when it presses on valve-seat in one position of theactuator, a leaktight bellows disposed around the actuating lever,connected to said lever by a first extremity and connected to thestationary body by the other extremity.
 7. Regulator of claim 6 in whichthe valve-seat is plane and the flap is fastened to the first end ofactuating lever by orientation adjustment means.
 8. Regulator of claim 6in which the valve-seat is conical and the check-valve spherical. 9.Regulator of claim 6 comprising at least one primary valve controlled bya first actuator including bistable electromagnetic control means and atleast one secondary valve controlled by a second actuator includingmonostable electromagnetic control means, the first and second valvesbeing designed to be placed in the given order in a fluid supplycircuit.
 10. Regulator of claim 9 comprising two first valves controlledsimultaneously by the first actuator and two second valves controlledsimultaneously by the second actuator, the first and second valves beingdesigned to be placed in the given order in two parallel fluid supplycircuits.
 11. Actuator as claimed in claim 2 in which the various typesof electromagnetic control means comprise monostable control means andbistable control means.
 12. Actuator of claim 11 in which the monostablecontrol means comprise a trip coil, the two spacers including a magneticspacer and a nonmagnetic spacer disposed on either side of the tripcoil.
 13. Actuator of claim 11 in which the bistable control meanscomprise a permanent magnet placed between two trip coils, the twospacers being non-magnetic and positioned on either side of the tripcoils.
 14. Actuator of claim 12 in which the bistable control meanscomprise a permanent magnet placed between two trip coils, the twospacers being non-magnetic and positioned on either side of the tripcoils.
 15. Actuator of claim 4 in which the bistable control meanscomprise a permanent magnet placed between two trip coils, the twospacers being non-magnetic and positioned on either side of the tripcoils.
 16. Regulator of claim 7 comprising at least one primary valvecontrolled by a first actuator including bistable electromagneticcontrol means and at least one secondary valve controlled by a secondactuator including monostable electromagnetic control means, the firstand second valves being designed to be placed in the given order in afluid supply circuit.
 17. Regulator of claim 8 comprising at least oneprimary valve controlled by a first actuator including bistableelectromagnetic control means and at least one secondary valvecontrolled by a second actuator including monostable electromagneticcontrol means, the first and second valves being designed to be placedin the given order in a fluid supply circuit.
 18. Regulator of claim 16comprising two first valves controlled simultaneously by the firstactuator and two second valves controlled simultaneously by the secondactuator, the first and second valves being designed to be placed in thegiven order in two parallel fluid supply circuits.
 19. Regulator ofclaim 17 comprising two first valves controlled simultaneously by thefirst actuator and two second valves controlled simultaneously by thesecond actuator, the first and second valves being designed to be placedin the given order in two parallel fluid supply circuits.